Refrigerating apparatus



' P 9 E. J. L. HALLSTRO M 2,053,827

REERIGERAT'ING APPARATUS Filed Jan. 31, 1935 a W. m W 1 w E? H. H H W. 0L w l 4: 9a. f w m H n m M "a 7 u A M M Y Ma 9 Patented Sept. 8, 1936UNITED STATES REFRIGERATING A PARATUS Edward John Lees Hallstrom;Willoughby, New South Wales, Australia Application January 31, 1935,Serial No. 4,237

In Australia February 16, 1934 1 Claim.

This invention relates to improvements in refri erating apparatus, andparticularly, to the in-- termittent type of absorption apparatus oflimited capacity which is used largely. for domestic cool safes and thelike.

In known apparatus of the class referred to in which ammonia is used asthe refrigerant and is circulated throughout the system by the externalapplication of heat alternating with the absorptive capacity of watercontained in the system, attention is required to regulate theapplication of heat and its discontinuance at the right time. Also acertain amount of water tends to migrate with the ammonia stream to thelow pressure side of the apparatus, and must be returned to the highpressure side in order to ensure satisfactory operation.

The invention consists in an absorption refrigerator of the type aboveindicated which is entirely automatic (save for the relighting of theburner for each cycle) requires no manual attention or manual movementof any part of it, and includes a heating element which furnishes heatat a predetermined rate and only for a predetermined time in eachoperation of the apparatus, means by which water which is carried fromthe boiler through the condenser and into the evaporator is returned tothe boiler at intervals and undue accumulation of water in theevaporator is thus prevented, means by which vuncondensed ammonia gaspassing out of the condenser or evaporated between the condenser andevaporator, is returned to the boiler, means whereby corrosion isinhibited on ironwork from which the galvanizing has been burnt byadjacent welding operations, an improved construction for the condenser,and a condenser cooling tank of such dimensions that it will functionefficiently with convection circulation.

Apparatus embodying the invention is illustrated in the accompanyingdrawing, in which:-

Fig. l is a diagrammatic elevation of the apparatus in operativerelation to the chamber to be cooled; and

Fig. 2 is a section to .an enlarged scale of means for preventingcorrosion of metal from which the galvanizing cover has been burnt offby welding in the pipe fitting operation.

In Fig. 1, H is a reservoir of definitely limited capacity having afilling hole and cap I2 and a connecting pip-e I3 from the reservoir IIto a, circular channel It forming the wick housing for the burner 15.The lowest edge 55 of the channel I4 is adjusted to be slightly higher,when erected for operation, than the highest level of kerosene orinflammable oil in the reservoir H. 16 is a wick preferably of fireresisting capillary material. The other portions of the burner 15 are ofknown design.

The complete heating element, which may consist of a plurality ofburners l5 fed with oil from the reservoir H, directs heat on to aboiler I! having lateral heat jacketing l8 and cooling fins I9, a vaporpipe 20 carried from the boiler up a closed separator 21 and terminatingat 22 under 10 a bell 23 which is supported above the top end 22 of thepipe 2%}, and has a pendent vent pipe surrounding the vapor pipe 26 andterminatingin an open end 24. From the top ,end of the separator 52! apipe 25 is led to the condenser 2,6. 5

The condenser consists of two equal length tubes of different diameters,2? and 28, assembled together concentrically, and closed at the ends .29to form an annular chamber with welded joints. The condenser may consistof a plurality of sections, joined by connecting pipes 353 and may beconstructed with external surfaces for air cooling, or, preferably, maybe water submerged in an open topped .casing Si, in which heat isremoved from the condenser by convection currents in the water.

From the condenser 26 a pipe 32 is connected to a liquor pipe 33 whichextends downwardly to the top of the evaporator 34. A liquor drain pipe35 extends from near the bottom of the evaporator 34, passing inside theliquor pipe 33 to 36 where the annulus between the pipes 33 and 35 isfilled in by welding. It is not essential, but is obviously convenientand advantageous to place the pipe 35 within the pipe 33, as it is thennecessary to make only onechannel 56 through the wall 'of therefrigerator chamber 58. A connection 31 extends from 38 to theseparator 2|, and radiating fins 38 are fitted (welded) to thisconnection; the purpose .of'this feature is described below.

From the liquor pipe 33, and adjacent to the junction of the pipe 32therewith, a gooseneck pipe 39, having the bend m at its highest point,extends down to an absorber H, and terminates at 42 near the bottomthereof, and the absorber 4| is connected to the separator 2i by upperand lower tubes 63 and 33. From the separator a tube 45, having itsupper end 36 open above the level of the absorber ll extends downtowards the bottom of the boiler at 31.

The refrigerator box or chamber 48 is adapted to have the evaporator 34positioned within it, the pipe 33 being sealed against leakage where itpasses through the chamber wall at 56.

Where the condenser 26 is submerged in a water tank 3| which is of thinmetal galvanized to prevent corrosion, welding is necessary in order tomake a watertight and rigid joint at 50, where the pipe 25 passesthrough the tank wall. The heat of welding burns the zinc coating offthe metal adjacent to the weld, and as it is impracticable to restore azinc coating to the metal near the weld within the tank, the thin pipemetal would rapidly corrode through at that point. In Fig. 2, 25 is thepipe, 5| the wall of the tank 3|, 52 a hole therein of larger diameterthan the pipe 25, 53 is a cup welded at the rim 54 to the wall of thetank, and having its bottom perforated for and welded to the pipe 25.During the welding the galvanizing is burnt off the interior of the cupat 55. The bared surface of the cup from which the galvanizing has beenlost is protected by pouring molten bitumen or other such substancethrough the hole 52 to fill the annulus 56.

In operation a definite quantity of suitable liquid fuel is placed inthe tank II and the burners are then lighted. The system is initiallysupplied with ammonia and water in definite proportion and amount,sealed in, and at the begining of distillation the boiler is full ofstrong liquor. During distillation evolved ammonia gas passes up thetube 20, together with a small proportion of entrained water. Thisascending vapor column passes into the bell 23 from the outlet 22 of thetube 20, and then passes out of the vapor tube at 24 into water which isretained at the level of the top 46 of the return tube 45; some of theentrained water is caught in the body of water in the separator. Theammonia vapor rises through the water and passes from the separator 2|through the pipe 25 to the condenser 26, still carrying with it someentrained water.

Most of the ammonia gas is condensed in the condenser, and passes asammonia liquor with some water through the pipe 32 and the pipe 33 tothe evaporator 34, where it stays until distillation ceases.

The amount of liquid fuel is adjusted by the size of the fuel reservoirtank I I as sufficient for one distillation of the ammonia contained inthe system, and when the liquid fuel is exhausted the burners l5extinguish and the boiler I! cools down, the cooling being promoted bythe radiation of heat from the fins [9. The water in the boiler l1, thuscooled, becomes capable of reabsorbing the ammonia which was dischargedduring boiling, drawing it from the evaporator 34 through the pipes 33and 39 into the absorber and thence into the separator and pipes 32 and25 into the separator, and from the separator discharging at 41 into thebottom of the boiler. The bell 23 closes the opening of the pipe 22 whendistillation ceases. The rate at which this absorption takes place isproportional to the rate at which heat from the refrigerator chamberpasses through the walls of the evaporator 34 and evaporates the ammoniatherein. When all the ammonia from the evaporator has been absorbed bythe water in the boiler, the burners are refuelled and again lighted,the distillation process is then repeated.

During the distillation period, the liquor passing from the condenser 26to the evaporator 34 carries some uncondensed gas. This separates fromthe ammonia liquor by gravity, and ascends the pipe 39 through thegooseneck trap pipe 40. The gooseneck bend is at a higher level than thecondenser, and consequently gas passed through it is delivered into theabsorber 4 I, in which water which circulates via the pipes 43 and 44absorbs the gas and the enriched liquor passes to the separator 2|.

When distillation is complete, the liquefied ammonia fills theevaporator 34 and stands at some higher level in the pipes 32 and 39.This hydraulic head forces some of the ammonia drawn from the bottom ofthe evaporator 34 up the pipe 35, and through the pipe 31 into theseparator 2|. This fractional purge serves to remove some of the ammoniarich in water from the evaporator, and so prevents the system frombecoming water-logged in the evaporator.

The fins 38 prevent heat creeping along the metal of the pipe 31 fromthe separator 2! to the condensed liquor which is passing down the pipes32 and 33 during the distillation period.

The pipe 39 may be returned to the separator, and the absorber thuseliminated, but the use of the absorber is preferable.

What I claim as my invention and desire to secure by Letters Patent is:-

Refrigerating apparatus of the kind herein described, comprising incombination, a boiler, means for applying heat thereto, a separator, astand pipe extending upwardly into the separator and arranged to conductvapor from the boiler to the separator and to discharge said vapor intoa chamber within the upper part of the separator, said chamber having adepending tube extension, a condenser in which vapor from the separatoris condensed, a pipe from the separator to the condenser, an evaporatorand an absorber, a pipe arranged for passing liquid from the condenserto the evaporator, and a pipe arranged for passing vapor from the upperportion of the evaporator to the absorber, the last mentioned pipeincluding a loop adapted to by-pass uncondensed gas to the absorber,upper and lower connections between the absorber and the separator, apipe arranged for passing unevaporated liquid from a low point in theevaporator to the gas space in the separator, and an overflow pipearranged to permit return of liquid from the separator to the boiler.

EDWARD JOHN LEES HALLSTROM.

